Abstract: An outer circumferential surface of a piston ring has a cut surface forming a notched portion between an outer circumferential end surface and a lower surface, the cut surface including a first surface between the outer circumferential end surface and a bottom portion, and a second surface between the bottom portion and the lower surface. The second surface is inclined away from a central axis of the piston ring as it extends toward a crank chamber side, an angle of inclination of the second surface with respect to the bottom portion being greater than or equal to 50° and less than or equal to 85°. When an axial width of the piston ring is h1 and a distance in an axial direction between a connecting portion between the cut surface and the outer circumferential end surface and a connecting portion between the cut surface and the lower surface is H, H/h1 is greater than or equal to 0.2 and less than or equal to 0.4.

Abstract: The present invention addresses the problem of providing a CrN coating film which has excellent peeling resistance such that peeling thereof starting at a crack is unlikely to occur even in a more severe lubrication environment. The problem is solved by a CrN coating film which has a preferred orientation of 200 as determined by XRD, and in which the X-ray diffraction intensity ratio of the (200) plane with respect to the (111) plane, (200)/(111), is 5.5 or higher, and the ratio of crystal grains of 1 ?m or smaller is 85% or higher in a crystal grain size distribution measured by an EBSD analysis.

Abstract: An outer peripheral surface of a compression ring includes a barrel curved surface, in a case where a width of the outer peripheral surface in an axial direction of the compression ring is set as L1, a condition of 0.2 mm?½×L1 is satisfied, and in a case where a distance in a radial direction of the compression ring between an outer peripheral peak and each of two points on the barrel curved surface separate from the outer peripheral peak by 0.1 mm in the axial direction of the compression ring is set as d1, and a distance in the radial direction of the compression ring between the outer peripheral peak and each of two points on the barrel curved surface separate from the outer peripheral peak by ¼×L1 in the axial direction of the compression ring is set as d2, a condition of d1<d2 is satisfied.

Abstract: An oil control ring comprises: an oil ring having a pair of land parts arranged in a sliding direction and connected to each other by a web part; and a coil expander that biases the oil ring toward the outer circumferential side in the radial direction. The web part of the oil ring is provided with a plurality of window holes. In the axial cross-sectional view of the largest opening portion of the window hole in the axial direction of the oil ring, a width H1 in the sliding direction of the oil ring and a length L1 of a combustion chamber-side non-window hole part, which excludes the window hole, in the outer circumferential surface of the web part, satisfy the condition of 0.15>L1/H1?0.

Abstract: A mold used for centrifugal casting includes a mold body formed in a cylindrical shape and a lid member (40) that is detachably assembled to an end part of the mold body in an axial direction. The lid member includes a lid body (41) that is attached to an opening part formed at the end part of the mold body, a protrusion part (450) that is fitted to the mold body, and a spring that applies elastic force to the lid body in a direction in which the lid body closely contacts the mold body.

Abstract: Provided is a cylinder liner which can reduce the friction of the sliding surface from conventional levels and improve fuel efficiency without increasing oil consumption from conventional levels. When the inner circumferential surface of a cylinder liner or cylinder bore used in an internal combustion engine has a first sliding region, a second sliding region, and a third sliding region, and when respective surface roughness Rvk is from 0.05 ?m to 0.3 ?m, from 0.4 ?m to 1.5 ?m, and from 0.15 ?m to 0.7 ?m, a friction can be reduced while maintaining oil consumption.

Abstract: A combination of piston rings assembled to a piston includes a first compression ring, a second compression ring, a third compression ring and an oil ring. When an axial width of the first compression ring is h1(1), an axial width of the second compression ring is h1(2), an axial width of the third compression ring is h1(3) and an axial width of the oil ring is h1(4), h1(1)?h1(2) and h1(1)?h1(3), and when h1(TOTAL)=h1(1)+h1(2)+h1(3)+h1(4), h1(TOTAL)?3.9 mm.

Abstract: A combination of piston rings assembled to a piston of an internal combustion engine includes four compression rings. An outer peripheral surface of a first compression ring includes a barrel surface, an outer peripheral surface of a second compression ring includes an outer peripheral end portion and a taper surface, an outer peripheral surface of a third compression ring includes an outer peripheral end portion and a taper surface, and an outer peripheral surface of a fourth compression ring includes an outer peripheral end portion and a taper surface.

Abstract: An outer peripheral surface of a piston ring has a cut surface provided to form a cutout portion between an outer peripheral end portion and a lower surface, the cut surface includes a curved concave surface, an inclination angle of a tangent of the curved concave surface at a point closest to the combustion chamber side on the curved concave surface, with respect to a first virtual line extending in parallel to the lower surface is equal to or greater than 5° and equal to or less than 50°, and in a case where an axial direction width of the piston ring is set as h1, and an axial direction width of the cut surface is set as H, H/h1 is equal to or greater than 0.2 and equal to or less than 0.4.

Abstract: A thermoelectric conversion module includes a base material having heat insulation properties and carbon nanotube yarn that is helically wound around the base material, P-type parts and N-type parts are alternately arranged and are series-connected in an extension direction of the carbon nanotube yarn, one side part of a helix formed by the carbon nanotube yarn is formed as a heat reception part, and the other side part across the base material from the one side part is formed as a heat dissipation part, lengths of the P-type parts and lengths of the N-type parts are shorter than a length of a one-turn portion of the helix, and the P-type parts and the N-type parts are arranged such that respective one end parts are included in the heat reception part and respective other end parts are included in the heat dissipation part.

Abstract: The present invention solves a novel problem of corrosive wear that occurs in the use of a valve seat in an internal combustion engine using a hydrogen gas fuel. The problem is solved by an iron-based sintered alloy valve seat used in an internal combustion engine using a hydrogen gas fuel, in which the Cr content is 6% by mass to 23% by mass, the Mo content is 5% by mass to 20% by mass, the Cu content is 10% by mass to 23% by mass, the Co content is 3% by mass or more, and a total content of Cr, Mo, and Co is 14% by mass to 47% by mass.

Abstract: A combination of piston rings assembled to a piston includes a first compression ring, a second compression ring, a third compression ring and an oil ring. When an axial width of the first compression ring is h1(1), an axial width of the second compression ring is h1(2), an axial width of the third compression ring is h1(3) and an axial width of the oil ring is h1(4), h1(1)?h1(2) and h1(1)?h1(3), and when h1(TOTAL)=h1(1)+h1(2)+h1(3)+h1(4), h1(TOTAL)?3.1 mm.

Abstract: Provided are a valve guide made of an iron-based sintered alloy excellent in wear resistance and thermal conductivity, and a method of producing the same. Specifically, provided are a method of producing a valve guide made of an iron-based sintered alloy, the method including the steps of: molding raw material powder including diffusion-alloyed powder including core iron powder and Cu bonded to the core iron powder through diffusion to obtain a molded body; and sintering the molded body, to thereby produce a valve guide made of an iron-based sintered alloy, and a valve guide produced by the production method.

Abstract: An object of the present invention is to provide a sliding member coated with a DLC coating in which microfractures on the sliding surface thereof due to the progression of cracks are less likely to occur, and in which an increase in abrasive wear can be reduced. The present invention achieves the above-mentioned object by a sliding member having a DLC coating on the outer peripheral surface thereof, wherein an S band derived from sp3 bonding is observed in the DLC coating in addition to a G band derived from the graphite structure and a D band derived from the defects of the graphite structure, and these bands satisfy specific relationships.

Abstract: An object of the present invention is to provide a sliding member coated with a DLC coating in which microfractures on the sliding surface thereof due to the progression of cracks are less likely to occur, and in which an increase in abrasive wear can be reduced. The present invention achieves the above-mentioned object by a sliding member having, on the outer peripheral sliding surface thereof, a DLC coating in which the amount of plastic deformation work as measured by a nanoindentation test is within a specific range.

Abstract: The present invention addresses the problem of providing a sintered alloy valve guide capable of inhibiting valve adhesion even in a high-temperature environment. The problem can be solved by a sintered alloy valve guide impregnated with a lubricating oil including pores that are sealed on the valve guide outer circumferential surface. More particularly, the problem is solved by the sealing step of performing a sealing treatment of pores on the outer circumferential surface of a sintered body impregnated with a lubricating oil.

Abstract: The present invention addresses the problem of providing a sintered alloy valve guide capable of inhibiting valve adhesion even in a high-temperature environment. The problem can be solved by a sintered alloy valve guide impregnated with a lubricating oil including pores that are sealed on the valve guide outer circumferential surface. More particularly, the problem is solved by the sealing step of performing a sealing treatment of pores on the outer circumferential surface of a sintered body impregnated with a lubricating oil.

Abstract: The present invention addresses the problem of providing a cylinder liner or a cylinder bore, which can reduce not only friction on a sliding surface but also oil consumption. In a piston sliding direction of the cylinder bore, grooves of a second sliding region positioned on the side of crankcase have a higher groove area ratio at a depth of 0.3 ?m than grooves of a first sliding region positioned on the side of combustion chamber, and the groove area ratio is in a specific range, whereby friction and oil consumption can be reduced.

Abstract: In a surface of a wire, a first side surface forming an outer circumferential surface in a piston ring includes a tapered surface and a protruding surface, the protruding surface is divided into a first part and a second part by a first virtual surface extending from the tapered surface, and the first part includes a top and is formed in a protruding shape.

Abstract: A cylinder liner of the present invention is a cylinder liner mounted on a cylinder block and formed of flaky graphite cast iron, at least a nitrided layer is provided on an inner periphery of the cylinder liner, and a cross hatching section is formed on the inner periphery, a roughness curve of the inner periphery has a plateau honing shape, a ten-point average roughness Rz of the inner periphery pursuant to JIS B0601:1982 is 4.0 ?m or less, and an average value of an area ratio of pits generated in the inner periphery is 8% or less.